Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
ShoutOUT - All in one business texting tool to send personalized alerts, promotions, reminders, short links and marketing campaigns, for any SMEs (hotels, restaurants, education, non profits, Woocommerce, banks, healthcare, agencies, supermarkets, weddings)
Twilio - Brings voice and messaging to your web and mobile applications.
Trumpia - SMS Marketing and Marketing Automation software for Mass SMS, internal communications & emergency alerts. #1 Text Messaging Service used by Fortune 500s.
Atomic SMS Sender - Free bulk SMS software to send bulk text messages from PC
Clickatell - Simple, reliable mobile messaging cloud.